Percentage calculator
Calculate percentages online, including percent of a number, percentage increase, and percentage decrease.
Date calculator
Add or subtract days, weeks, months, or years from a date. Shows the weekday, day of year, and week number of the result.
How to use Date calculator
Add or subtract years, months, weeks, and days from any date to find a deadline, due date, or anniversary.
- Month math clamps to the end of the month, so January 31 + 1 month = February 28 (or 29)
- Optionally count days as business days to skip weekends
- Shows the weekday, day of the year, ISO week number, and quarter
To count the days between two dates, use the days between dates calculator.
Date calculator FAQs
Is Date calculator free?
Date calculator is a free online tool on ReallyUseful.Tools. No account is required.
Does Date calculator run in my browser?
Date calculator is designed to run in your browser where supported, so files can stay on your device instead of being uploaded to a server.
More Calculators
Age calculator
Calculate exact age from date of birth in years, months, days, and more with a simple online age calculator.
BMI calculator
Calculate your BMI online using height and weight. Get body mass index results with metric and imperial units.
Mortgage calculator
Estimate monthly mortgage payments with loan amount, interest rate, term, deposit, taxes, and fees.
Loan calculator
Calculate loan payments, total interest, and repayment schedules for personal loans and other borrowing.